kellogg



Jan. 3, 1928. I 1,654,977

E. W. KELLOGG VACUUM TUBE CIRCUITS Invenbdr":

Edward W. Kel I egg;

His Atmor'neg- Patented Jan. 3, 1928.

UNITED STATES EDWARD.W. KELLOGG, OF SGHENEGTADY, NEW YORK, ASSIGNOR 'I'O GENERAL ELEC- TRIG COMPANY, A CDRPORA'IION 01E NEXV YORK.

vncuumrunn crno'ortrs.

Original application filed October 5, 1922, Serial No. 592,605. Divided and this application filed May 10, l 1924. Serial No. 'ilfBAtZ.

My present invention relates particularly to circuit arrangements for amplifying and detecting high frequency signaling currents by means of three electrode electron discharge devices employing the principle of electrostatic current control, although it is not limited in its application to this method of control, but may be employed with de vices embodying the electromagnetic principle of current control. This application is a division of my prior application, Serial No. 592,605, filed October 5, 1922. r

The object of my invention is to provide improved circuit arrangements whereby the number of separate devices necessary to employ to secure a desired result may be re duced by permitting of the use of a single device to serve different functions.

It has heretofore been proposed to employ an electron discharge device both for radio and audio frequency signal amplification. I havediscovered that a device employed for audio frequency 'amplification may at the same time beemployed as an oscillator for generating the local frequency oscillations for separate heterodyne reception thus permitting of the use of all of the devices employed in a receiving and amplifying system for two purposes. For example, in a system employing three electron discharge devices, one device may serve both for radio and audio frequency amplification a second device for audio frequency amplification and generating oscillations, and the third device as a detector-and amplifier as in the separate heterodyne system.

The novel features which I believe to be characteristic of my invention are set forth with particularity in theappended claims. My invention itself, however, both as to its organization and method of operation will best be understood by reference to the following description taken in connection with the accompanying drawing in which Figs. 1,2 and 3 show diagrammatically different circuit arrangements in which all of the devices employed serve double functions.

In Fi 1I haveshown a continuous wave amplifying and detecting system employing three tubes 13, 14 and 15. Tube13 is connected as a regenerative amplifier and detector. The grid circuit of tube 13 includes a resonant circuit 2 which is tuned to the signal frequency; The plate circuit of tube 13 includes a feed-back coupling coil 5 which is coupled to the antenna coupling coil 6 or to the tuned circuit 2, or both, and permits of regen rative amplification. The usual grid condenser 7 and grid leak 8 cause thedevice to also function as a detector. The audio frequency current produced in the plate circuit of tube 13 is supplied by transformer 16 to the grid circuit of tube 14:. A tuned circuit 17 in the grid circuit of tube 1 1 is coupled by coupling 18 to the plate circult to produce the local oscillations which are impressed by means of the coupling 19 upon the grid circuit of tube 13. Tube 14: thus acts audio frequency amplifier and oscillator. The output from the plate circuit of tube 1 1 is supplied by the audio frequency transformer 20 to the grid. circuit of tube 15, which thus acts as an audio frequency amplifier. The receiving telephones 21 are connected to the plate circuit of tube 15 inthe usual manner. Extra windings 22 and 23 may be supplied upon the transformers 16 and 20 connected to the jacks 24; and 25 to permit connecting the telephone receivers to the output circuits of tubes 13 and 14 if desired. The plate circuits of all of the tubes are supplied with current from a single source 26. The primary windings of transformers 16 and 20 are preferably shunted by lay-pass condensers 27 to permit the passage of high frequency currents flowing in the plate circuits. 1

In Fig. 2 I. have shown a slightly different three tube arrangement. In this case tube 29 serves as an oscillator to feedlocal oscillations to the grid circuit of tube 30. which acts as adetector. by means of the shielded connecting links 31. The transformer 32 in the plate circuit of tube 30 supplies audio frequency currents to the grid circuit of tube tonne coupling circuit 38, in the jack 39, Which is connected in the grid circuit of tube 34:. By ineansot' the coupling the ampliiied high frequency currents from the plate circuit of tube 34 are supplied to the grid circuit of detector tube 30. A jack i1 may also be provided in the grid circuit of detector 30 to permit of the impressing oi the received signaling currents directly upon the grid circuit 01": the detector.

To prevent undesired reactions between the different stages of amplification series reactances 4-2 and shunt condensers l3 will preferably be employed in the plate supply circuits. A low pass filter e-l 's also pre erably inserted in the plate circuit of detector tube 30.

The arrangement shown in 8 is similar to that shown in F 2 with the exception that means is provided in this case whereby tube 29 may serve both as radio frequency amplifier and audio frequency amplifier, the jack permitting of the llllpressing otthe received signaling currents directly on the grid circuit oi? tube 29. Tube 34: may serve both as audio frequ ncy ampl fier and radio frequency an'iplitier in Fig.

2. In case the arrangement is to be employed.

for the reception of interrupted continuous Waves, spark signals or radio telephony, the feed back connection 46 may be Zliljtliitlt toiregenerative amplification. the system is to be employed for receiving continuous wave telegraphic signals, the tuning and feedback may be adjusted so that tube 30 serves as a self-heterodyne detector.

What I claim as new and desire to secure by Letters Patent of the United States is w 1. A. heterodyne signal receiving system comprising an electron discharge device connected to serve as a detector and a second electron discharge device connected to produce oscillations and supply them to the detector, said second device being also connect ed to amplify audio frequency currents pro duced by said detector.

2. The combination in a signal receiving system of a plurality of electron discharge devices having plate and control circuits connected in cascade arrangement, means for supplying high frequency signaling energy to the first of said devices which is connect ed to serve a detector, means for feeding audio frequency currents from the plate circuit of the first device to the controlcircuit ot' a second device which is connected to generate high frequency current, and means for feeding high frequency current generated by rose-err the second device to the control circuit of the first device.

3. The combination in a signal receiving system of a plurality of electron discharge devices having plate and control circuits, one of said devices being adapted to serve as a detector, and another oi said devices being adapted to serve as an audio frequency amplifier, means for ipplying lo the control circuit oi the amplifier audio frequency variations produced in the plate circuit of the detector and means for supplying to the control circuit of the de'ector high frequency currents generated in the audio frequency amplifier circuits.

A signal receiving system comprising a pair of electron discharge devices each having plate and control circuits, a coupling between the plate circuit or one device anu the control circuit of the second device, re generative connections external to the devites lJQl'WLQD the plate and control circuits of each dc 'ice and a coupling between the plate circuit or the second device and the control circuit of the first device.-

5. A. signal Mceiving system comprising a pair of electron discharge devices having plate and control circuits, a coupling be tween the plate circuit of one device and the control. circuit of the second device, regenera i connections external to the devices between the plate and control circuits oi each device, the control circuit of the first device being resonant to the signal frequency, and the control circuit of the second device being resonant to a dill'erent radio frequency, and a coupling between the plate circuit of the second device and the grid circuit of the first device.

6. 1 signal receiving system comprising a pair oi? electron discharge devices having plate and control circuits, a coupling be tween the plate circuit or one device and the control circuit oi the second device, regenen alive connections external to the devices between the plate and control circuits of each device, the control circuit of the first device being resonant to the signal frequency. and the control circuit oil. the second device bcing' resonant to a diilcreut radio lrequcucy. and a coupling between the plate circuit of the second device and the grid circuit ot the first device, the first device being connected to serve as a detector.

In witness whereof, l have hereunto set my hand this 9th day of llluy, 192i.

nnivilnn iv. sucrose. 

